1. Field of the Invention
The present invention relates in general to anti-theft car protection systems and more particularly to the anti-theft car protection systems of a type which uses a microcomputer. More specifically, the present invention is concerned with an anti-theft car protection system which uses, as a part thereof, the microcomputer which controls operation of the engine of the associated vehicle.
2. Description of the Prior Art
Nowadays, many motor vehicles are powered by electrically controlled internal combustion engines for the reasons of high responsive, reliable, powerful and economical operation of the same.
One of such engines is shown in Japanese Patent First Provisional Publication 55-151133. The engine is controlled by an electronic centralized control system "ECCS". For controlling the engine operation, the system "ECCS" has an electrical control unit "ECU" which comprises a microcomputer. When an ignition key cylinder is turned to "START" position, a crank shaft is driven by a starter motor and at the same time a controlled amount of fuel is injected into the engine, so that the engine starts. That is, upon turning of the ignition key cylinder to "START" position, the electrical control unit "ECU" calculates the pulse width of a control pulse signal which is to be applied to each of the fuel injection valves at the engine start. The pulse width represents the open period of the injection valve, so that the amount of fuel fed to the engine corresponds to the pulse width.
However, almost all of such engines have no defense against a thief. That is, if a short circuit is illegally made by a car thief handling a pick, wire or the like in the engine start circuit, the engine is permitted to start. In this case, the car can be easily stolen off by the thief.